We are studying the role of ascorbic acid and neoplastic transformation in regulating collagen metabolism in animal cells. Deficiency of ascorbate in guinea pigs leads to decreased proline hydroxylation and defective collagen synthesis, but in different time sequences. The mechanism by which synthesis is decreased is being investigated. The mechanism by which the proportion of type III collagen increases in Kirsten sarcoma virus transformed BALB 3T3 cells is also being determined.